Problems with driver 402 resolved by downgrading to driver 381 as suggested by Fanatec Support
It's funny, as Fanatec have the latest official driver firmware for a DD1 listed as Driver 400, however I was recommended to use a previous official driver 381 by Fanatec Support and I have to tell you, it feels great!
I really don't see the need to move past this and what all the fuss is about to find the so called "Holly Grail of FFB" setting for these wheels!
Try 381 again, or if you haven't already. Particularly if you are having constant game crashes like I have. You can hardly notice the difference and it's super smooth.
Thanks Fanatec Support for the fast response too.